1. Field of the Invention
The subject invention is directed to metal cutting system and, in particular, to a metal cutting system adapted to permit effective coolant delivery to an interface between a metal cutting tool and a workpiece.
2. Background of the Invention
Metal cutting tools for performing metal working operations generally comprise a cutting insert having a surface terminating at a cutting edge and a tool holder formed with a seat adapted to receive the insert. The cutting insert engages a workpiece and removes a chip therefrom. Obviously, it is desirable to lengthen the life of a cutting insert in metal cutting operations. Longer insert life leads to lower operating costs and better machine efficiency. One factor in the life of a cutting insert is the temperature of the insert during cutting operations. A higher insert temperature will result in a shorter useful life of an insert.
3. Description of the Related Art
Many systems have been designed to lower the insert temperature during cutting. For example, coolants may be generally applied through nozzles directed at the cutting edge of the insert. The coolant serves not only to lower the temperature of the insert but also to remove the chip from the cutting area. The nozzles are often a distance of 1-12 inches away from the cutting edge. This is too far of a distance for effective cooling. The farther the coolant must be sprayed the more the coolant will mix with air and the less likely it will be to actually contact the tool-chip interface.
Some have improved cooling by directing high pressure and high volume coolant at the cutting edge as shown in U.S. Pat. No. 6,045,300 issued to Antoun. Others have designed grooves between the insert and a top plate that secures the insert in the holder to reduce the distance the coolant must be sprayed. This is shown in U.S. patent application serial number 2003/00820118 to Kraemer. Some have delivered liquid nitrogen as the coolant relatively near the cutting edge of an insert as shown in U.S. Pat. No. 5,901,623 issued to Hong. Each variation has shown limited effectiveness. Many still are positioned to far from the tool-workpiece interface. Those with grooves between the top plate and the insert get fluid closer to the tool-workpiece interface but are not close enough. The design in Kraemer is also limited in that the direction of fluid flow is almost completely limited to one plane. The liquid nitrogen system like that in Hong has shown some benefit but is cost prohibitive for most applications. It is clear there remains a need for a simple and effective assembly for insert cooling during metal cutting operations.